The present invention relates to disk type record storage apparatus, particularly to that apparatus which provides enhanced medium-to-transducer spacing and stabilization.
For successful magnetic recording, particularly at high densities, such as employed in storage apparatus for use with digital computers, data communication links and the like, there should be a predictable constant spacing between a record medium and a transducer over a wide range of operating parameters. Such spacing has a substantial effect, particularly at high densities, on the fringing flux pattern such that resolution of the sensing and recording on a record medium is significantly affected. Unfortunately, in flexible media record storage apparatus, the interaction of many parameters has a substantial effect on the predictability and maintainability of such desired constant spacing. Such parameters which effect the spacing include relative speed between the record medium and the transducer, contour of the surface areas surrounding the transducer, penetration of the transducer/stabilizer into the record medium (dimpling), radial position, as well as the disk storage substrate parameters, such as flexibility, thickness and so forth. Additionally, temperature and humidity can have a significant effect on variations of medium-to-transducer spacings.
For ensuring constant spacing between a record medium and a transducer, it is preferred that the transducer penetrate or dimple into the flexible record medium. In single disk storage apparatus of the Bernoulli type, such desired penetration at the outer radial portion of the single record disk may cause the Bernoulli effect to be destroyed. Further, such radial outward portions of Bernoulli stabilized record storage disks tend to flutter. This fluttering results in a variation of transducer spacing. Accordingly, the outer radial extent of the usable recording area is limited by such fluttering and adaptability of the record storage disk to accept penetration.
Such Bernoulli supported record storage disks are mounted on a spindle for rotation adjacent a backing plate usually referred to as a Bernoulli plate. It has been found that the spacing between the Bernoulli plate and the record storage disk, hence the spacing between the transducer and the record storage disk, varies as a function of disk radius. As one goes radially outwardly, the spacing of the record storage disk tends to become closer to the backing or Bernoulli plate. It was found that this spacing varies as the function of the disk radius raised to the minus two-thirds power. Accordingly, it is also desired to increase the radial extent of the recording area by reducing the disk to Bernoulli plate spacing adjacent the center of rotation while maintaining the Bernoulli effect throughout the radial extent of the record storage disk, at least in the area where the transducer is operatively associated with such record storage disks.